The following Patent Document 1 discloses a molding die that is used to coat an optical fiber and is used to form a mold portion including a first mold groove and a second mold groove by coupling a first base on which the first mold groove is formed to a second base on which the second mold groove is formed; a first position-adjusting groove into which a position-adjusting member is to be fitted is formed on a surface on which the first mold groove of the first base is formed; a second position-adjusting groove into which a position-adjusting member is to be fitted is formed on a surface on which the second mold groove of the second base is formed; a resin injection passage that is used to inject resin into the mold portion is formed on at least one of the first base and the second base; a first resin discharge groove that is used to discharge the resin from the mold portion is formed across the first mold groove and the first position-adjusting groove on the surface on which the first mold groove of the first base is formed; a second resin discharge groove that is used to discharge the resin from the mold portion is formed across the second mold groove and the second position-adjusting groove on the surface on which the second mold groove of the second base is formed; two first resin discharge grooves and two second resin discharge groove are provided thereon; and the two resin discharge grooves are positioned so as to sandwich the resin injection passage therebetween.